This invention relates to an apparatus for compounding a polymeric reaction product, and more particularly to a combination reaction-mixing vessel for the preparation of acrylic polymers.
In many orthopedic surgical procedures it is necessary to employ a bonding material to set implants such as pins and artificial joints in bone. The cement which is employed for this purpose is generally a polymeric material which is prepared by copolymerization of its components as needed. Because of the necessity for a fairly quick setting material the cement is almost universally prepared by a surgical assistant during the course of the operation right in the sterile field of the operating room. The preparation of the cement involves admixture of the cement components in a suitable reaction vessel to form a uniform polymeric reaction product. The cement is usually an acrylic material, comprising a reaction product of methylmethacrylate monomer and polymethylmethacrylate-methylmethacrylate-styrene copolymer. In order to provide a cement which has the desired properties and which has the desired fixation of the implants it is necessary that the compounds be uniformly and thoroughly admixed so that a homogeneous reaction product is produced. During mixing and the consequent reaction there are produced various vapors which may comprise a gaseous form of a volatile component or a gaseous reaction product. Because of the noxious and toxic nature of such vapors it is highly undesirable to be exposed to them, particularly for extended periods of time in the course of multiple preparations. Since it is necessary that mixing be carried out for a period of up to four or five minutes in order to insure a uniform reaction product and a minimum concentration of volatile reactants, the period of exposure to harmful vapors can be substantial.
It is an object of this invention to provide an apparatus for mixing acrylic bone cement which is capable of producing a uniform admixture of reactants.
Another object of the invention is to provide an apparatus which provides safe and effective operation in the preparation of acrylic polymers.
A further object of the invention is to provide a mixing device from which fumes and gaseous reaction products can be removed and conveyed to a remote location for disposal.
Another object of the invention is to provide a safe and easily operable mixing-reaction vessel which is disposable after use.
A still further object of the invention is to provide for consistent mechanical mixing of acrylic cement reactants without exposure of the operator to toxic or noxious by-products.